Various equipment has been devised in the past for compression of crop materials, such as, hay into small wafers or cubes with the desirable end of reducing waste, permitting storage or shipment of the hay in a compact condition and making it easier to handle, for example, in the feeding of animals. Typically, after the hay is picked up in the field it is transferred to a pelleting machine where the hay is compressed and separated into individual wafers or pellets and thereafter collected in a separate receptacle. Broadly, it is well-known to apply compressive forces to the hay by passing it through a pelleting zone formed by co-planar, counter-rotating press wheels between which the hay is compressed and divided into a highly dense package. Representative of such apparatus are those disclosed in the U.S. Pat. Nos. 1,094,320, 2,052,449, 3,023,559 and 3,430,583. However, equipment using such apparatus is not commercially available and has presented some difficulties and limitations in that it will not tolerate a very wide variation in feeding rates of the hay and does not establish the speed and precompression of the hay necessary for high rate production from a given size or capacity of machine. For instance, precompression of the hay into a dense stream permits the use of smaller press wheels and the regulating of the cross-sectional size of the stream for most efficient feeding through the press wheels in final compression and cubing or pelleting of the hay. Otherwise, if the stream of hay leading into the press wheels is too large in relation to the diameter of the press wheels, the angle of the pressure between the hay and the press wheels is such as to oppose the motion of the hay. Moreover, increased speeds of the stream of hay at a controlled size permits use of smaller press wheels and associated drive trains. For these and other reasons, it is important that the condition size and density of the hay be closely controlled from its point of introduction into the machine through the final compression stage for most efficient, high speed production rates.